Method of wrapping or packaging plastic materials and a machine for carrying out the method



April 28, 1959 A c, (js 2,883,811

METHOD OF WRAPPING 0R PACKAGING PLASTIC MATERIALS AND A MACHINE FOR CARRYING OUT THE METHOD Filed Dec. 8, 1955 2 Sheets-Sheet 1 INVENTIOR CARL A. OSTERN METHOD OF WRAPPING OR PACKAGING PLASTIC MATERIALS AND A MACHINE FOR CARRYING OUT THE METHOD April 28, 1959 A TERM 2,883,811

Filed Dec. 8, 1955 2 Sheets-Sheet 2 FIG/A.

INVENTOAR CARL A. OSTERN United States Patent METHOD OF WRAPPING OR PACKAGING PLAS- TIC MATERIALS AND A MACHINE FOR CARRY- ING OUT THE METHOD Carl Anton Ostern, Eugene, .Hurum, Norway, assignor to Norsk Spraengstofindustri -A-/-S, Oslo, Norway Application December 8, 1955, Serial No. 551,941

7 Claims. (Cl. 53-123) This invention relates to apparatus for wrapping or packaging plastic materials.

The invention is particularly, but not exclusively .intended for wrapping plastic explosive material and is hereinafter described in connection with the so-called cartridging of gelatinous dynamite or like gelatinized explosives. It is, however, to be understood that the invention can also be used for wrapping other plastic explosives and other plastic materials.

When wrapping gelatinized dynamite to form cartridges it is important to avoid high pressures in case a foreign body might be included :in the mass of dynamite. Therefore, metal elements which press against one another, for example toothed wheels, should be avoided as far as possible. This requirement is taken into account in the apparatus of the present invention. Another circumstance which gives rise to particular difiiculty in the handling of dynamite .is that the mass :is pasty and, therefore, easily sticks to parts with which it comes into contact.

For making gelatinized dynamite into cartridge form one known method is to roll out the dynamite mass into a band of a thickness approximately corresponding to .the desired diameter of the dynamite cartridge, and to feed the band forwards and divide it into a number of parallel strands. These strands, however, are so close together that the further treatment becomes difiicult. In this known method, therefore, each second strand is removed and these strands are re-fed to the machine.

The present invention relates to a process similar to that described, an important feature of the invention being that, instead of removing each second strand of the parallel strands, all the strands are guided away from one another, and thereafter fed forwards as parallel strands with intervening spaces between them. The Wrapping with paper then takes place during this parallel forward feeding of the strands. Usually the strands are cut into lengths before being wrapped with paper. The term strand as used in the present description and the accompanying claims also includes a strand which is cut into lengths.

The cutting of the strands into the desired lengths can take place either before the strands are separated from one another, or after they have been separated.

The wrapping with paper and cutting into the desired lengths can be accomplished in different ways. According to one preferred method the paper is conveyed in the form of cut pieces. It has been found that difiiculties are encountered when the paper is supplied in lengths greater than the length of the dynamite cartridges, in such a manner that the dynamite is at approximately the same distance from the ends of the piece of paper. This is due to the fact that the adhesiveness of the dynamite prevents the movement of the dynamite cartridges from being arrested or slowed down relative to the movement of the conveyor bands which feed the cartridges forwards. This difiiculty is overcome, in accordance with a further feature of the invention, by first wrapping the ice material with a paper of approximately the :same length as the length of the cartridge and then with a paper of somewhat greater length. Usually the material :is -.cut .into desired lengths before being wrapped with the first paper, but it is also possible to wrap the continuous strands with paper and then .cut the wrapped material into desired lengths.

After the first wrapping the cartridges can be handled more easily, and when they arrive at the place where the paper for the second wrapping is supplied, they are temporarily arrested, after which they are released to be fed forward further together with the paper .in the correct position in relation thereto. Between the first and second wrapping with paper the cartridge preferably trawe'ls at a faster speed than its original speed, for the purpose of separating the individual cartridges in the longitudinal direction.

The pieces cut from all the strands, after they have been wrapped with paper, are preferably fed further in a plane at right angles to the first direction of feed, the ends of the paper being bent inwardly and the paper, if desired, being impregnated and dried.

A machine for carrying out the method of the invention comprises rollers for rolling out plastic material into the form of a band, knives for cutting the band of material into parallel strands, knives for cutting the strands into lengths and conveyor bands for feeding the bandand the strands forward. The machine :is characterized in particular by a plurality of conveyor bands, the number of which corresponds to the number of strands into which the material is divided, which bands diverge in the direction of feed, and further separate conveyor bands constituting prolongations of the said first-men,- tioned conveyor bands, and apparatus co-operating with the conveyor bands for simultaneously wrapping with paper the material which is fed forwards in the parallel strands. The above-mentioned separation of the strands is effected by the machine, .and a number of strands which are parallel to one another and disposed in the same plane can be wrapped. Due .to "the adhesiveness of the gelatinized dynamite such separation cannot be obtained by means of guides which guide the strands away from each other on a wide conveyor belt.

A preferred embodiment of a machine in accordance with the invention is illustrated diagrammatically sand-by way of example in the accompanying drawing, in which Figures 1 and 1A taken together :are a side elevation of those parts of the machine in which the separation :of the strands and the wrapping of the material with paper takes place. The rolls for pressing a mass of gelatinized dynamite into the form of a band, as well as the parts of the machine where the bending of the ends of the paper takes place, are not illustrated in the drawing.

Figure 2 is a plan view of the part of the machine of Figure 1 where the separation of the strands takes place.

Referring to the drawing the reference numeral 1 designates a conveyor band for feeding a plastic mass, for example gelatinized dynamite, in the form of a rolled band 2. The reference numeral 3 designates a separating device having a number of parallel circular knives which divide the band 2 into a number of parallel strands 4 which are conducted with the aid of belt 5 to conveyor belts 6, the number of which corresponds to the number of strands 4. The belts 6 are carried at their ends on pulleys 7 and 8 respectively. The numerals 9 and 10 represent guides for the belts with the aid of which the belts are guided from the roller 7, where they are close to one another, in such a way that they are parallel to one another, but spaced apart. The numeral 11 represents a separating drum having knives 12 which cut the strands into suitable lengths.

The reference numeral 13 designates a roll of paper which is mounted on a horizontal shaft which is not illustrated in the drawing. From the roll 13 is taken a strip of paper 14 which first passes over the guide roll 15 where an adhesive is applied to the paper by a roller 16 which dips into a bath 17 containing the adhesive.

A pair of rollers 18 withdraws the paper strip from the roll 13. A shears 19 cuts the paper into suitable lengths. After it has passed the shears 19 the paper passes between the rolls 20 and 21 and partly around a roll 21, the paper being guided by a plate 22. A conveyor band 23, which is guided around the roll 21 and also over rolls 24 and 25, and a folding sleeve 26 serve to wrap the paper around the piece of material. The reference 'numeral 27 shows a piece of material 27 round which paper has been wound. This piece of material is then deposited on a conveyor band 28 which is driven at a higher speed than the conveyor bands 6 and 23, so that the cartridges are separated from one another in the longitudinal direction.

A stop 29, when in the position illustrated in the drawing, prevents the wrapped piece from moving further towards the right. The stop 29 can be swung upwardly to release the cartridges. The movement of the stop 29 is accurately synchronized with an apparatus for feeding a piece of paper for the second wrapping of the cartridges. This apparatus corresponds exactly to the apparatus already described for feeding and wrapping the first layer of paper around the cartridges. The reference numerals 13' and 14' and so forth up to and including 26' indicate the parts corresponding to the parts 13 to 26 previously described. The reference numeral 30 represents the cartridge wrapped with the second layer of paper, the paper being slightly longer than the cartridge itself, so that it projects at both ends.

The invention of course, is not limited to the apparatus shown in the drawing. If materials which are not sticky are treated, the double wrapping with paper is not necessary. Also the wrapping with paper can take place in a difierent way from that illustrated in the drawing. The essential feature of the invention is the simultaneous treatment of a number of strands which is possible due to the strands formed by the distributing rollers 3 being guided apart by means of belts 6.

I claim:

1. A machine for packaging sticky materials, for example gelatinized dynamite, comprising rolls for rolling out the material into the form of a band, knives for cutting the band into parallel strands, knives for cutting the strands into lengths, conveyor bands for feeding the band, the strands, and the lengths of material forward, said conveyor bands including a separate conveyor band for each of the strands, which conveyor bands diverge in the direction of feed, further spaced, parallel conveyor 4 bands constituting prolongations of the first mentioned conveyor bands, and means for wrapping the lengths of material with paper while the material is being fed forwards on said further parallel conveyor bands.

2. A machine as claimed in claim 1, in which the diverging conveyor bands have parts at the divergent ends which are parallel.

3. A machine as claimed in claim 1, in which the means for wrapping the pieces of material with'paper comprise stationary folding sleeves, the further conveyor bands being guided through the sleeves.

4. A machine as claimed in claim 1, in which the means for wrapping the pieces of material with paper comprise stationary folding sleeves, one of the further conveyor bands being guided through each sleeve, a guide roller for the band being arranged shortly before its entry into the sleeve, and means for feeding paper from a supply roll and for cutting it into lengths immediately preceding said guide roller.

5. A machine as claimed in claim 1, comprising two sets of folding sleeves arranged one after the other with associated further conveyor bands and paper feeding devices.

6. A machine as claimed in claim 1, comprising two sets of folding sleeves arranged one after the other with associated further conveyor bands and paper feeding devices, and in which there is provided between the conveyor bands for the two sets of folding sleeves a set of conveyor bands moving at a higher speed than the preceding bands, said higher speed conveyor bands serving to separate the lengths of material in their axial direction before they reach the second set of folding sleeves.

7. A machine as claimed in claim 1, comprising two sets of folding sleeves arranged one after the other with associated further conveyor bands and paper feeding devices, and in which there is provided between the conveyor bands for the two sets of folding sleeves a set of conveyor bands moving at a higher speed than the preceding bands, and a stop adjacent said higher speed conveyor bands which is movable into the path of the pieces of material being fed forwards, the movement of the stop being synchronized with the paper feeding means in such a manner that the pieces of material are at approximately the same distance from the ends of the paper.

References Cited in the file of this patent UNITED STATES PATENTS 1,417,591 Anderson May 30, 1922 2,303,351 Gage Dec. 1, 1942 2,435,347 Gilman Feb. 3, 1948 2,605,597 Scheib Aug. 5, 1952 2,649,035 Cloud Aug. 18, 1953 2,655,777 Hagen Oct. 20, 1953 

